# US 9,438,906 B2 · Method of encoding an image into a coded image, method of decoding a coded image, and apparatuses thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,906 B2 - Document ID: US9438906B2 - Status: Granted - Kind: B2 - Application number: 13/810,540 - Filed: 2012-03-02 - Published: 2013-05-09 - Granted: 2016-09-06 - Earliest claimed: 2011-03-03 - Assignees: Sun Patent Trust - Applicants: Chong Soon Lim; Viktor Wahadaniah; Sue Mon Thet Naing; Hisao Sasai; Takahiro Nishi; Youji Shibahara; Toshiyasu Sugio - Inventors: Chong Soon Lim; Viktor Wahadaniah; Sue Mon Thet Naing; Hisao Sasai; Takahiro Nishi; Youji Shibahara; Toshiyasu Sugio - Web page: https://patentgrep.com/patent/US9438906B2 ## CPC - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers - H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter - H04N 19/172: the region being a picture, frame or field - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/50: using predictive coding (H04N19/61 takes precedence) - H04N 19/61: in combination with predictive coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method of encoding an image into a coded image, the method comprising: writing a quantization offset parameter into the coded image, determining a prediction mode type for coding a block of image samples of the image into a coding unit of the coded image, determining a quantization parameter for the block of image samples, and determining if the prediction mode type is of a predetermined type, wherein if the prediction mode type is of the predetermined type, the method further comprises: modifying the determined quantization parameter using the quantization offset parameter, and performing a quantization process for the block of image samples using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the method further comprises: performing a quantization process for the block of image samples using the determined quantization parameter. ## Claims ### Claim 1 A method of encoding an image into a coded image, the method comprising: writing a quantization offset parameter into the coded image, the quantization offset parameter being determined based on a difference between (i) a first quantization parameter of coding units of the image coded by a predetermined prediction mode, the predetermined prediction mode being of a predetermined type and (ii) a second quantization parameter of coding units of the image coded by another prediction mode different from the predetermined prediction mode; generating a predicted image sample for a block of image samples of the image based on a prediction mode type for coding the block of image samples into a coding unit of the coded image; determining a quantization parameter for the block of image samples; and determining if the prediction mode type is of the predetermined type, wherein if the prediction mode type is of the predetermined type, the method further comprises: modifying the determined quantization parameter using the quantization offset parameter; and performing a quantization process for the block of image samples using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the method further comprises: performing a quantization process for the block of image samples using the determined quantization parameter. ### Claim 2 (depends on 1) The method according to claim 1, wherein said modifying the determined quantization parameter comprises subtracting from the determined quantization parameter a value of the quantization offset parameter. ### Claim 3 (depends on 1) The method according to claim 1, wherein said writing the quantization offset parameter comprises writing the quantization offset parameter in one of a slice header, a picture header and a sequence header. ### Claim 4 (depends on 1) The method according to claim 1, the method further comprises writing a prediction mode type parameter indicating the determined prediction mode type in a header of the coding unit. ### Claim 5 (depends on 4) The method according to claim 4, the method further comprises: determining a delta quantization parameter; and writing the delta quantization parameter into the header of the coding unit, wherein the delta quantization parameter represents a value determined by subtracting from a quantization parameter of a previous coding unit a value of the determined quantization parameter. ### Claim 6 (depends on 5) The method according to claim 5, wherein the previous coding unit is defined as a coding unit immediately before the coding unit in accordance with a coding order of the coded image. ### Claim 7 (depends on 5) The method according to claim 5, wherein coding units of the coded image are represented in a quad-tree structure, and the previous coding unit is defined as a coding unit located at an immediate left of the coding unit based on the quad-tree structure, regardless of a coding order of the coded image. ### Claim 8 A method of decoding a coded image, the method comprising: retrieving a quantization offset parameter from the coded image, the quantization offset parameter being determined based on a difference between (i) a first quantization parameter of coding units of the image coded by a predetermined prediction mode, the predetermined prediction mode being of a predetermined type and (ii) a second quantization parameter of coding units of the image coded by another prediction mode different from the predetermined prediction mode; generating a predicted image sample for a coding unit of the coded image based on a prediction mode type of the coding unit of the coded image; determining a quantization parameter for the coding unit; and determining if the prediction mode type is of the predetermined type, wherein if the prediction mode type is of the predetermined type, the method further comprises: modifying the determined quantization parameter using the quantization offset parameter; and performing an inverse quantization process for the coding unit using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the method further comprises: performing an inverse quantization process for the coding unit using the determined quantization parameter. ### Claim 9 (depends on 8) The method according to claim 8, wherein said modifying the determined quantization parameter comprises subtracting from the determined quantization parameter a value of the quantization offset parameter. ### Claim 10 (depends on 8) The method according to claim 8, wherein said retrieving the quantization offset parameter comprises retrieving the quantization offset parameter from one of a slice header, a picture header and a sequence header. ### Claim 11 (depends on 8) The method according to claim 8, wherein the coding unit comprises a transform unit, and the method further comprises determining whether the transform unit is coded, wherein if the transform unit is determined to be coded, the method further comprises retrieving a delta quantization parameter for the coding unit from a header of the coding unit, and wherein if the transform unit is determined to be not coded, the method further comprises setting a delta quantization parameter for the coding unit having a value of zero. ### Claim 12 (depends on 11) The method according to claim 11, wherein said determining the quantization parameter comprising summing the delta quantization parameter and the quantization parameter of a previous coding unit. ### Claim 13 (depends on 12) The method according to claim 12, wherein the previous coding unit is defined as a coding unit immediately before the coding unit in accordance with a coding order of the coded image. ### Claim 14 (depends on 12) The method according to claim 12, wherein coding units of the coded image are represented in a quad-tree structure, and the previous coding unit is defined as a coding unit located at an immediate left of the coding unit based on the quad-tree structure, regardless of a coding order of the coded image. ### Claim 15 (depends on 11) The method according to claim 11, wherein said retrieving the prediction mode type comprises retrieving the prediction mode type from the header of the coding unit. ### Claim 16 An apparatus for encoding an image into a coded image, the apparatus comprising: a writing unit for writing a quantization offset parameter into the coded image, the quantization offset parameter being determined based on a difference between (i) a first quantization parameter of coding units of the image coded by a predetermined prediction mode, the predetermined prediction mode being of a predetermined type and (ii) a second quantization parameter of coding units of the image coded by another prediction mode different from the predetermined prediction mode; a prediction mode type decision unit for generating a predicted image sample for a block of image samples of the image based on a prediction mode type for coding the block of image samples into a coding unit of the coded image; a quantization parameter determining unit for determining the quantization parameter for the block of image samples; a quantization parameter computing unit for determining if the prediction mode type is of the predetermined type; and a quantization unit for performing a quantization process for the block of image samples, wherein if the prediction mode type is of the predetermined type, the quantization parameter computing unit is configured to modify the determined quantization parameter using the quantization offset parameter, and the quantization unit is operable to perform the quantization process for the block of image samples using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the quantization unit is operable to perform the quantization process for the block of image samples using the determined quantization parameter. ### Claim 17 An apparatus for decoding a coded image, the apparatus comprising: a parsing unit for retrieving a quantization offset parameter from the coded image, the quantization offset parameter being determined based on a difference between (i) a first quantization parameter of coding units of the image coded by a predetermined prediction mode, the predetermined prediction mode being of a predetermined type and (ii) a second quantization parameter of coding units of the image coded by another prediction mode different from the predetermined prediction mode; a decoding unit for generating a predicted image sample for a coding unit of the coded image based on a prediction mode type parameter from the coding unit of the coded image; a quantization parameter determining unit for determining a quantization parameter for the coding unit; a quantization parameter computing unit for determining if the prediction mode type is of the predetermined type; and an inverse quantization unit for performing an inverse quantization process for the coding unit, wherein if the prediction mode type is of the predetermined type, the quantization parameter computing unit is configured to modify the determined quantization parameter using the quantization offset parameter, and the inverse quantization unit is operable to perform an inverse quantization process for the coding unit using the modified quantization parameter, and wherein if the prediction mode type is not of the predetermined type, the inverse quantization unit is operable to perform an inverse quantization process for the coding unit using the determined quantization parameter.